A refrigerant metering system/method incorporating a manual expansion valve (MEV), condenser isolation valve (CIV), flow isolation valve (FIV), and evaporator isolation valve (EIV) is disclosed. The MEV is configured to replace a conventional automated expansion valve (AEV) that controls a refrigerant flow valve (RFV) that is positioned in a heating, ventilation, and air conditioning (HVAC) system between a refrigerant condenser coil (RCC) and a refrigerant evaporator coil (REC) and permits manual metering of refrigerant by the RFV from the RCC to the REC and also allows complete shutoff of refrigerant flow by the RFV from the RCC to the REC. The MEV allows rapid HVAC repair and restoration of service where a replacement AEV is not readily available. The CIV/FIV/EIV are positioned in the refrigerant flow lines to permit the AEV and/or REC to be isolated from HVAC refrigerant flow for repairs to the AEV and/or REC.

The disclosed technology includes devices, systems, and methods for heat pump systems configured to operate in low ambient temperatures. The disclosed technology can include a heat pump water heater system having an evaporator, a first compressor configured to compress refrigerant to a first pressure, and a second compressor configured to compress the refrigerant to a second pressure. The second pressure can be greater than the first pressure. The heat pump water heater system can include a preheater configured to receive the refrigerant at the first pressure and heat water and a condenser configured to receive the refrigerant at the second pressure and heat water. The water can be passed through the preheater before being passed through the condenser.

A refrigerant metering system/method incorporating a manual expansion valve (MEV), condenser isolation valve (CIV), flow isolation valve (FIV), and evaporator isolation valve (EIV) is disclosed. The MEV is configured to replace a conventional automated expansion valve (AEV) that controls a refrigerant flow valve (RFV) that is positioned in a heating, ventilation, and air conditioning (HVAC) system between a refrigerant condenser coil (RCC) and a refrigerant evaporator coil (REC) and permits manual metering of refrigerant by the RFV from the RCC to the REC and also allows complete shutoff of refrigerant flow by the RFV from the RCC to the REC. The MEV allows rapid HVAC repair and restoration of service where a replacement AEV is not readily available. The CIV/FIV/EIV are positioned in the refrigerant flow lines to permit the AEV and/or REC to be isolated from HVAC refrigerant flow for repairs to the AEV and/or REC.

A refrigerant metering system/method incorporating a manual expansion valve (MEV), condenser isolation valve (CIV), flow isolation valve (FIV), and evaporator isolation valve (EIV) is disclosed. The MEV is configured to replace a conventional automated expansion valve (AEV) that controls a refrigerant flow valve (RFV) that is positioned in a heating, ventilation, and air conditioning (HVAC) system between a refrigerant condenser coil (RCC) and a refrigerant evaporator coil (REC) and permits manual metering of refrigerant by the RFV from the RCC to the REC and also allows complete shutoff of refrigerant flow by the RFV from the RCC to the REC. The MEV allows rapid HVAC repair and restoration of service where a replacement AEV is not readily available. The CIV/FIV/EIV are positioned in the refrigerant flow lines to permit the AEV and/or REC to be isolated from HVAC refrigerant flow for repairs to the AEV and/or REC.

Heat pump systems with a gas bypass tank and that operate in both heating and cooling modes are disclosed. The systems include a first splitting valve that can route liquid refrigerant to either the indoor coil or the outdoor coil, depending on whether the heat pump system is in heating or cooling mode. An expansion valve in the system can lower the pressure of liquid refrigerant leaving a condenser, thereby creating a two-phase fluid comprising liquid refrigerant and vaporized refrigerant. The gas bypass tank can separate liquid refrigerant from vaporized refrigerant. The liquid refrigerant can be supplied to the evaporator of the system, while the vaporized refrigerant can be bypassed to a compressor. The first splitting valve can include a first plurality of switching paths that route the separated liquid refrigerant to either the outdoor coil or the indoor coil.

A refrigerant metering system/method incorporating a manual expansion valve (MEV), condenser isolation valve (CIV), flow isolation valve (FIV), and evaporator isolation valve (EIV) is disclosed. The MEV is configured to replace a conventional automated expansion valve (AEV) that controls a refrigerant flow valve (RFV) that is positioned in a heating, ventilation, and air conditioning (HVAC) system between a refrigerant condenser coil (RCC) and a refrigerant evaporator coil (REC) and permits manual metering of refrigerant by the RFV from the RCC to the REC and also allows complete shutoff of refrigerant flow by the RFV from the RCC to the REC. The MEV allows rapid HVAC repair and restoration of service where a replacement AEV is not readily available. The CIV/FIV/EIV are positioned in the refrigerant flow lines to permit the AEV and/or REC to be isolated from HVAC refrigerant flow for repairs to the AEV and/or REC.

A system includes a heat exchanger mounted to the brackets and receiving cryogen, the heat exchanger having a vertical inlet coupled in parallel to a plurality of equal size horizontal tubes each traversing a width of the heat exchanger and further coupled in parallel to a vertical outlet pipe with an outlet diameter at least twice an inlet tube diameter; a temperature sensor; a thermostat that monitors the temperature sensor and maintains a predetermined temperature set point by communicating with a solenoid valve coupled to the heat exchanger; an exhaust line coupled to the outlet pipe that expels exhaust gas outside the enclosed facility; multiple fans attached to the heat exchanger; and a fail-safe oxygen sensor to protect a biological object in the enclosed facility.

A refrigeration system includes a heat exchanger configured to place a cooling fluid in a heat exchange relationship with a working fluid, a free-cooling circuit having a pump configured to circulate the working fluid through the heat exchanger and a condenser, a flow control valve configured to control a flow rate of the working fluid to the condenser, a condenser bypass valve configured to control a flow rate of the working fluid that bypasses the condenser, and a controller configured to adjust a position of the flow control valve, a position of the condenser bypass valve, a speed of a fan of the condenser, a speed of the pump, and a temperature of a heater based on an ambient temperature, a temperature of the working fluid leaving the condenser, the position of the flow control valve, the position of the condenser bypass valve, or a combination thereof.

An oil separator has a filter portion in a differential pressure generation mechanism configured to collect, by a differential pressure, lubricating oil that is in a form of mist included in high-pressure refrigerant that flows in a first pipe that is connected to a discharge port of a compressor and allows the collected lubricating oil to move downstream along an internal wall of the first pipe.

A load balancing method for two compressors. The two compressors are used in a refrigeration system and are driven coaxially by the same driving device. The method comprises the steps of obtaining parameters, determining balance, and controlling start/stop states. The parameters in the step of obtaining parameters are parameters related to the two compressors, such as a compressor suction side flow rate, or exhaust side flow rate, or suction side temperature; the step of determining balance comprises determining, on the basis of the obtained parameters related to the two compressors, whether load is balanced between the two compressors; the step of controlling start/top states comprises controlling the start/stop states of the two compressors according to whether the load is balanced. The method can monitor the load balance state of two compressors that are coaxially driven, thereby effectively avoiding failure of the refrigeration system caused by unbalanced loads of the compressors.